Wireless Local Area Network (LAN) provides connection using radio frequencies, unlike wired LAN for communication using a cable. The wireless LAN can be configured using an Access Point (AP) that provides wireless access. The AP configures one wireless LAN by setting a frequency band, a Service Set IDentifier (SSID), and a security scheme. The AP is given the same wireless LAN name as the SSID and informs adjacent terminals of its information, including the SSID, by periodically sending a predefined signal. The terminals can be referred to as stations.
To access a particular wireless LAN, a terminal searches for adjacent APs through a scanning procedure. According to the search, the terminal can select and access one AP. In so doing, when a security mode of the AP is not open, input of a security password is requested. The security password is defined by the selected AP according to the corresponding security scheme. When the security mode of the AP is open, the terminals can access the AP without inputting the security password.
A malicious AP owner may let the terminals easily access and obtain every data transmitted and received by the connected terminals by setting the security mode of the AP to open. That is, since all data transmitted and received by the terminals over a core network passes through the AP, the AP can acquire all the data. When the SSID of a well-known wireless network service provider is pirated, such a problem can be aggravated.